This invention relates, in general, to portable electronic devices manufactured using automated assembly processes, and particularly to impact-tolerant mounting of acoustic components (microphones, speakers, buzzers and the like) within such devices.
By way of example, the invention is described in connection with the automated manufacture of a telephone handset of known type, and particularly in connection with the mounting of a microphone sub-assembly within the handset. By "impact tolerant" is meant that the component is so mounted (particularly important in portable devices) for withstanding relatively severe mechanical shocks such as caused by the dropping of the portable device.
As last steps in the manufacture of a telephone handset, a fairly rigid substrate, which may comprise one or more printed circuit boards with various electronic/optical components mounted thereon, is sandwiched between two molded plastic housing halves which are snap-fitted or otherwise fastened together. These last steps are well suited for automated assembly processes using relatively simple robotic (programmed) tools. A complication in the assembly process, however, relates to the mounting of a microphone sub-assembly which must also be mounted within the telephone handset.
In one arrangement, the microphone sub-assembly comprises a quite small circular cylinder having end ports for admitting sound to a transducer within the cylinder and a two-part molded plastic or hard rubber container snap-fitted around the microphone cylinder. The container serves a number of roles: it encloses and protects the microphone (as well as providing one or more internal acoustic sound chambers); it provides a preselected configuration for firm mounting of the container within the handset housing; and it provides a sealed exit port for wires from the microphone to a wire terminating connector which, as part of the assembly process, is snap-fitted within a mating connector on the component containing substrate.
The afore-mentioned complication presented by the microphone sub-assembly is that it is quite difficult to assemble the subassembly into the handset. Thus, in addition to the steps of picking-up and properly orienting and mounting the sub-assembly, the connector at the end of the microphone wires must be inserted into its mating connector on the substrate, and the microphone wires must be properly nested within the handset housing. If the wires are not properly nested, they can be pinched between the two housing halves when they are snap-fitted together. This, of course, causes numerous problems. Indeed, owing to the difficulty of assembling the microphone sub-assembly into the handset housing, such assembling is generally done by hand rather than, as preferred, by machine.
Additionally, although the microphone sub-assembly end connector is press-fitted into its mating connector, for firm fit, experience has shown that the connector all too frequently comes loose when quite common handling accidents occur, e.g., the dropping of the telephone handset.
These problems are addressed by the present invention.